Silicone Hydrogel Contact Lens

ABSTRACT

Ophthalmically compatible contact lenses include lens bodies configured for placement on a cornea of an animal or human eye. The lens bodies are made of a hydrophilic silicon-containing polymeric material. The lens bodies have oxygen permeabilities, water content, surface wettabilities, flexibilities, and/or designs to be worn by a lens wearer even during sleep. The present lenses can be worn on a daily basis, including overnight, or can be worn for several days, such as about thirty days, without requiring removal or cleaning.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/213,437, filed Aug. 26, 2005, which claims the benefit of U.S.Provisional Application No. 60/604,961, filed Aug. 27, 2004 and U.S.Provisional Application No. 60/621,525, filed Oct. 22, 2004, thecontents of which in their entireties are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

The present invention relates to contact lenses which are wearable, on acontinuous basis, for extended periods of time. In particular, theinvention relates to flexible, hydrophilic silicon-containing contactlenses which have advantageous combinations of properties.

Contact lenses are fundamentally classified into soft and hard typelenses. Hard contact lenses are literally hard and can be somewhatuncomfortable to wear. On the other hand, soft contact lenses are morecomfortable to wear, but are commonly removed from the eye at the end ofeach day. Soft contact lenses are classified as hydrogel lenses andnon-hydrogel lenses.

Conventional soft hydrogel contact lenses are often composed ofcopolymers of hydrophilic monomers, such as hydroxyethylmethacrylate,N-vinylpyrrolidone and the like, and can be prepared by lathe-cuttingmethods, spin casting methods, cast molding methods or combinationsthereof, followed by a swelling treatment in a physiological salineand/or phosphate buffer solution to obtain lenses with water contents ofabout 20% or about 30% to about 80% by weight.

Soft silicon or silicone hydrogel contact lenses have been suggested forcontinuous wear for extended periods of time. For example, some siliconehydrogel contact lenses are intended to be worn overnight. Some siliconehydrogel contact lenses can be worn continuously for about two weeks,and some silicone hydrogel contact lenses can be worn continuously forabout one month or about thirty days. Such continuous wear lenses havehad relatively high oxygen permeabilities to provide for oxygen accessto the cornea during the extended wearing of such lenses.

Oxygen permeability (Dk) is an important factor in contact lens designto maintain ocular health for contact lens wearers. As established byHolden and Mertz in 1984, a minimum of 87×10⁻⁹ (cm ml O₂)/(sec ml mmHg)oxygen transmissibility is required for hydrogel contact lenses to limitovernight edema to 4% (Holden et al., Invest. Ophtalmol. Vis. Sci.,25:1161-1167 (1984)). Physical properties such as oxygen flux (j),oxygen permeability (Dk), and oxygen transmissibility (Dk/t) are used inreferring to properties of contact lenses. Oxygen flux can be defined asa volume of oxygen passing through a specified area of a contact lensover a set amount of time. The physical units of oxygen flux can bedescribed as μl O₂ (cm² sec). Oxygen permeability can be defined as theamount of oxygen passing through a contact lens material over a setamount of time and pressure difference. Physical units of oxygenpermeability can be described as 1 Barrer or 10⁻¹¹ (cm³ O₂ cm)/(cm³ secmmHg). Oxygen transmissibility can be defined as the amount of oxygenpassing through a contact lens of specified thickness over a set amountof time and pressure difference. The physical units of oxygentransmissibility can be defined as 10⁻⁹ (cm ml O₂)/(ml sec mmHg). Oxygentransmissibility relates to a lens type with a particular thickness.Oxygen permeability is a material specific property that can becalculated from lens oxygen transmissibility.

Oxygen transmissibility is commonly measured using polarographic andcoulometric techniques known by persons or ordinary skill in the art.Oxygen permeability can be calculated by multiplying the oxygentransmissibility (Dk/t) of a lens by the mean thickness of the measuredarea. However, it appears that the polarographic techniques may notprovide accurate measurements for high Dk silicone hydrogel contactlenses, such as silicone hydrogel contact lenses having a Dk greaterthan about 100 barrers. The variability associated with polarographictechniques may be related to the issue that for silicone hydrogel lenseshaving a Dk greater than 100 barrers, the measurements tend to plateauat Dk values greater than 100. The coulometric technique is frequentlyused to measure the Dk of lenses that are believed to have Dks greaterthan 100 barrers.

Prior art soft silicon-containing hydrophilic contact lenses with higherwater contents tend to have reduced or lower oxygen permeabilities. Forexample, a silicone hydrogel contact lens available under the tradename,Focus Night & Day (available from CIBA Vision Corporation), has a watercontent of about 24% and a Dk of about 140 barrers. Another siliconehydrogel contact lens available under the tradename, O2 Optix (availablefrom CIBA Vision Corporation), has a water content of about 33% and a Dkof about 110 barrers. Another silicone hydrogel contact lens availableunder the tradename, Acuvue Oasys (available from Johnson & Johnson),has a water content of about 38% and a Dk of about 105 barrers. Anothersilicone hydrogel contact lens available under the tradename, PureVision(available from Bausch & Lomb), has a water content of about 36% and aDk of about 100 barrers. Another silicone hydrogel contact lensavailable under the tradename, Acuevue Advance (available from Johnson &Johnson), has a water content of about 46-47% and a Dk of about 65barrers. In comparison, a non-silicone hydrogel contact lens availableunder the tradename, Acuvue2 (available from Johnson & Johnson), has awater content of about 58% and a Dk of about 25 barrers.

In addition, existing silicone hydrogel contact lenses have a modulusfrom between about 0.4 to about 1.4 mPa. For example, the Focus Night &Day contact lens has a modulus of about 1.4 mPa, the PureVision contactlens has a modulus of about 1.3 mPa, the O2 Optix has a modulus of about1.0 mPa, the Advance contact lens has a modulus of about 0.4 mPa, andthe Oasys contact lens has a modulus of about 0.7 mPa. In general, forexisting silicone hydrogel contact lenses, as the Dk increases, themodulus of the lens increases.

Furthermore, existing silicone hydrogel contact lenses do not havedesirable surface wettabilities. For example, the Focus Night and Daycontact lens has a wetting angle of about 67°, the PureVision contactlens has a wetting angle of about 99°, the O2 Optix contact lens has awetting angle of about 60°, and the Advance contact lens has a wettingangle of about 107°. In comparison, non-silicone hydrogel contact lenseshave wetting angles of about 30°.

It is important that contact lenses be comfortable and safe to wear. Forexample, silicone hydrogel contact lenses should be comfortable and safeto wear for daily use, for overnight wear, and/or for wearing on anextended or continuous wear basis. One problem that arises in extendedor continuous wear contact lenses is adhesion of the lens to the corneaduring lens wearing which can result in wearer discomfort, eyeirritation, corneal staining and/or other damage to the eye. Althoughlenses with high water contents are softer and more comfortable to wear,such prior art lenses may not have one or more properties useful toprovide comfortable and safe wearing of the contact lenses. For example,existing contact lenses may not have a desirable Dk, a desirable surfacewettability, a desirable modulus, a desired design, and/or a desirablewater content. For example, silicone hydrogel contact lenses with a highDk typically have a lower water content. In addition, such lenses aremore stiff compared to lenses with a higher water content, and suchlenses are less wettable.

To reduce stromal anoxia during daily wear of contact lenses, it isdesirable to produce a lens that has an oxygen transmissibility of atleast about 45. Lenses, such as certain existing silicone hydrogelcontact lenses, with an oxygen transmissibility greater than 50 havebeen developed to reduce stromal anoxia during daily wear.

To help improve the properties of silicone hydrogel contact lenses, somelenses have been produced which include one or more surface treatmentsor surface modifications to attempt to make the lens surfaces morehydrophilic. Other lenses have been produced which include aninterpenetrating network of polyvinylpyrollidone and asilicon-containing polymer.

There continues to be a need for new silicone hydrogel contact lenseswhich have advantageous combinations of properties such as, enhancedflexibility or less stiffness, better wettability, and/or better lensdesigns.

SUMMARY OF THE INVENTION

New contact lenses have been invented. For example, contact lenses whichcomprise a hydrophilic silicon-containing polymeric component (e.g.,silicone hydrogel contact lenses) have been invented. The present lensescan be understood to be associated with one, two, or more of thefollowing features, a natural wettability (e.g., an untreated surfacewettability), a high Dk, a high water content, a low modulus, anddesigns that facilitate wearing the contact lenses with reduceddiscomfort. For example, the present lenses have one or more of theforegoing properties when compared to existing silicone hydrogel contactlenses. Or, stated differently, the present lenses have different valuesof one or more of the foregoing properties. The properties of thepresent lenses lead to reduced discomfort to the lens wearer wearing thepresent contact lenses compared to existing silicone hydrogel contactlenses.

In certain embodiments, the present silicone hydrogel contact lenseshave one or more surfaces that are not treated to become morehydrophilic, have no wetting agents, and/or are associated with low orno protein or lipid deposition.

In certain embodiments, the present silicone hydrogel contact lenseshave a relatively high Dk and a relatively high water content comparedto existing silicone hydrogel contact lenses, such as those describedherein. For example, the present silicone hydrogel contact lenses mayhave an equilibrium water content from about 30% to about 60% by weight,and a Dk from about 200 barrers to about 80 barrers. In one embodiment,a silicone hydrogel contact lens has an equilibrium water content from20% to 70% by weight, and a Dk from 220 barrers to 60 barrers. Oneexample of the present silicone hydrogel contact lenses has anequilibrium water content of about 30% by weight and a Dk of about 200barrers. In certain embodiments, the present lens has an equilibriumwater content greater than 20% by weight and a Dk greater than 160barrers. Another example of the present silicone hydrogel contact lenseshas a water content of about 60% by weight and a Dk of about 80 barrers.In one embodiment, a silicone hydrogel contact lens has a water contentgreater than 50% by weight and a Dk greater than 70 barrers. Yet anotherexample of the present silicone hydrogel contact lenses has a watercontent of about 48% by weight and a Dk greater than 100 barrers. Thus,it can be understood that the present silicone hydrogel contact lensesmay have higher water content and higher Dk relative to existingsilicone hydrogel contact lenses.

Certain embodiments of the present silicone hydrogel contact lenses havea relatively higher Dk and a relatively lower modulus compared toexisting silicone hydrogel contact lenses, as described herein. Forexample, the present silicone hydrogel contact lenses may have a Dk fromabout 100 to about 200 barrers, and a modulus from about 0.4 mPa toabout 1.4 mPa. One example of a silicone hydrogel contact lens has a Dkgreater than 90 barrers and a modulus from 0.3 mPa to 1.5 mPa. Incertain embodiments, the present silicone hydrogel contact lenses have aDk of about 100 and a modulus of about 0.4 mPa. In other embodiments,the present silicone hydrogel contact lenses have a Dk of about 200 anda modulus of about 1.4. In yet other embodiments, the present siliconehydrogel contact lenses have a Dk of about 150 barrers and a modulus ofabout 0.8 mPA. In comparison, the existing Acuvue Advance siliconehydrogel contact lens has a modulus of about 0.4 mPa and a Dk of about70. The existing Focus Night & Day silicone hydrogel contact lens has amodulus of about 1.4 and a Dk of about 130. Thus, certain embodiments ofthe present silicone hydrogel contact lenses have a relatively greaterDk, a relatively higher water content, and are relatively softer thanexisting silicone hydrogel contact lenses.

The present silicone hydrogel contact lenses may comprise surfaces thathave a greater wettability than existing silicone hydrogel contactlenses, such as those silicone hydrogel contact lenses described herein.As understood by persons of ordinary skill in the art, the wettabilityof a contact lens surface can be determined by measuring the wettingangle using a method, such as the sessile drop method. Lower wettingangles correspond to enhanced surface wettability. For purposes ofcomparison, existing silicone hydrogel contact lenses, such as thosedescribed herein, have surfaces that provide a wetting angle from about60° to about 110°. The present silicone hydrogel contact lenses maycomprise surfaces, such as the anterior and/or posterior surface, thathave a wetting angle less than 60°. In certain embodiments, the presentsilicone hydrogel contact lenses have surfaces that have a wetting angleless than about 50°. In further embodiments, the present siliconehydrogel contact lenses have surfaces that have a wetting angle of about30°. At least one example of the present contact lenses has a surfacethat has a wetting angle less than 40°. The present contact lenses withthe lower wetting angle, and therefore, enhanced surface wettability,have higher Dks, higher water contents, and/or lower modulus compared toexisting silicone hydrogel contact lenses, as discussed herein.

The present lenses may provide improvement or enhancement in patientcomfort compared to existing silicone hydrogel contact lenses, asdiscussed herein. For example, whereas only about 15% of patientswearing existing silicone hydrogel contact lenses reported satisfactorycomfort wearing the lenses, about 40% of patients wearing the presentsilicone hydrogel contact lenses reported satisfactory comfort wearingthe lenses.

In one specific embodiment, the present contact lenses have a Dk fromabout 115 to about 149 barrers, a water content of about 48% by weight,and a modulus of about 0.84 mPa. For example, a contact lens may have aDk greater than 105 barrers, a water content greater than 45% by weightand a modulus greater than 0.8 mPa. In certain embodiments, the presentsilicone hydrogel contact lenses have a water content greater than about50% by weight, a modulus from about 0.3 to about 0.5 mPa, and a Dk fromabout 70 to about 100 barrers. For example, a contact lens may have awater content greater than 50% by weight, a modulus from 0.2 mPa to 0.6mPa, and a Dk greater than 60 barrers. Such embodiments may be useful asdaily wear silicone hydrogel contact lenses. In additional embodiments,the present silicone hydrogel contact lenses have a Dk of at least about120 barrers and a water content of at least about 48% by weight. Suchembodiments may be useful as extended or continuous wear siliconehydrogel contact lenses. By way of comparison, as discussed herein, theAcuevue Advance silicone hydrogel contact lens has a Dk of about 105, awater content of about 46% by weight, and a modulus of 0.7 mPa.

The present lenses are hydrophilic, and have unique and advantageouscombinations of properties as described herein. The combinations ofproperties are helpful in evaluating appropriate conditions for wearingthe present lenses. For example, certain combinations of properties,such as high water content, relatively lower Dk, and low modulus may bedesirable or acceptable for daily wear silicone hydrogel contact lenses,such as lenses that can be worn overnight without cleaning, but that aretypically disposed of on a daily basis. Other combinations ofproperties, such as high Dk, high water content, and low modulus may beeffective in facilitating the use of such lenses in continuous orextended wear applications, such as for more than one night, such as forat least about five days, for example about two weeks or more, or atleast about one month. The present contact lenses can be relativelyeasily and cost effectively produced. Using such lenses providesadvantages, such as, vision correction with reduced lens handling andmaintenance, continuous or extended wearing of contact lenses, whilebeing ophthalmically compatible and providing for wearer comfort andsafety.

In one broad aspect, contact lenses comprise lens bodies that areconfigured to be placed or disposed on a cornea of an animal or humaneye. The lens bodies comprise a hydrophilic silicon-containing polymericmaterial or materials. The lens bodies have Dk's or oxygenpermeabilities of greater than about 70 barrers or about 80 barrers orabout 100 barrers or about 105 barrers or about 110 barrers or about 115barrers or about 120 barrers or about 125 barrers or about 130 barrersor about 150 barrers or about 180 barrers or about 200 barrers or moreand equilibrium water contents of greater than about 15% or about 30% orabout 35% or about 40% or more by weight. The present contact lenses areophthalmically compatible, and advantageously are adapted and structuredand/or are effective for continuous wear on a cornea of a human oranimal eye, for example, for 1 day or 5 days or at least about 5 days ormore.

In one embodiment, the lens body, that is the ophthalmically compatiblelens body, of the present contact lens, does not have, for example, isproduced without, surface treatment or modification, such as on theanterior face and/or posterior face of the lens body. In certain priorart lenses such surface treatment was required to enhance surfacewettability and/or one or more other properties of the lenses.

The present lenses, advantageously have ophthalmic compatibility withoutrequiring such surface treatment or modification. For example, thepresent lenses can be produced by polymerizing a lens precursorcomposition in a contact lens mold assembly to form a contact lens thatcan undergo extraction and packaging steps without requiring apost-polymerizing surface modification to remain sufficiently wettablewhen placed on an eye of an individual. In addition, some embodiments ofthe present lenses do not require polyvinylpyrollidone (PVP), such as aPVP containing interpenetrating network, and/or other additivies, toobtain the desired wettability of the present lenses. In certainembodiments, the present lenses are free of a surface modification orsurface treatment and do not include a PVP-containing interpenetratingnetwork. In other words, the present contact lenses can be produced bypolymerizing or curing a lens precursor composition in a contact lensmold and extracting and hydrating the polymerized lens. The hydratedlens produced in the mold includes an anterior surface and/or posteriorsurface that is sufficiently wettable to be worn on an eye with reduceddiscomfort or without substantial discomfort, to a lens wearer, andwithout requiring a surface treatment. Thus, embodiments of the presentinvention may be understood to be non-surface treated silicone hydrogelcontact lenses.

In one embodiment, the lens bodies of the present contact lenses mayhave a combination of properties, including an effective or appropriateionoflux to substantially inhibit, or even substantially prevent,corneal staining, for example, corneal staining more severe thansuperficial or moderate corneal staining, after the contact lens is worncontinuously on a cornea of a human or animal eye for 8 hours or more,for example, for about 1 day, or about 5 days, or about 10 days, orabout 20 days or about 30 days or longer.

The oxygen permeability of the present lens bodies may be measured withthe contact lens in the wet or fully hydrated state. The oxygenpermeability or Dk is expressed as barrers, that is 10⁻¹⁰ (ml O₂mm)/(cm² sec. mm Hg) or 10⁻¹⁰ ml O₂ mm cm⁻² sec.⁻¹ mm Hg⁻¹. Preferably,the lens body has a Dk of at least about 80 barrers or about 100 barrersor about 105 barrers or about 110 barrers or about 115 barrers or about120 barrers or about 125 barrers or about 130 barrers, or at least about150 barrers or about 180 barrers, or even at least about 200 barrers ormore. The larger values of Dk of the present lens bodies are highlyuseful in that oxygen is substantially accessible to the cornea of aneye even when a contact lens is located on the cornea continuously froma prolonged period of time, as described herein.

The present lens bodies may have effective or appropriate structural ormechanical characteristics, such as modulus, tear strength, elongationand/or one or more of the like properties, to withstand continuouscontact lens wear for extended or prolonged periods of time, asdescribed herein. For example, present lens bodies may have effective orappropriate modulus for use as continuous wear contact lenses.

The present contact lenses include a lens body comprising a hydrophilicsilicon-containing polymeric material. In one embodiment, the polymericmaterial comprise units from a silicon-containing monomer, for example,from two silicon-containing macromers having different molecularweights, and preferably different chemical structures. Such anembodiment may be particularly useful for continuous wear siliconehydrogel contact lenses, such as silicone hydrogel contact lenses thatcan be worn continuously for about 30 days. In another embodiment, thepresent contact lenses comprises only one silicon-containing macromerhaving a relatively high molecular weight. This embodiment, that is theembodiment comprising one silicon-containing macromer may beparticularly useful for daily wear silicone hydrogel contact lenses thatcan be worn while sleeping, but that are typically discarded on a dailybasis.

Each and every feature described herein, and each and every combinationof two or more of such features, is included within the scope of thepresent invention provided that the features included in such acombination are not mutually inconsistent. In addition, any feature orcombination of features may be specifically excluded from any embodimentof the present invention.

These and other aspects and advantages of the present invention willbecome apparent in the following detailed description, examples andclaims.

DETAILED DESCRIPTION

The present contact lenses have unique and advantageous combinations ofproperties which facilitate the use of such lenses for prolonged wearingof the contact lenses by lens wearers. For example, the present lensescan be worn while a person sleeps. In certain embodiments, the lenseshave properties that facilitate the use of the lenses for daily wear,which can include overnight wear. In other embodiments, the lenses haveproperties that facilitate use of the lenses in continuous or extendedwear applications, such as for more than 5 days (e.g., for about 30days). The present contact lenses provide advantages, such as, visioncorrection with reduced lens handling and maintenance, continuous orextended wearing of contact lenses, and being ophthalmically compatibleand/or providing for wearer comfort and safety.

In one broad aspect, the present invention provides silicone hydrogelcontact lenses that comprise a non-surface treated lens body. The lensbody comprises a hydrophilic, silicon-containing polymeric material, andhas at least one of an oxygen permeability, a water content, a surfacewettability, a modulus, and a design that is effective in facilitatingophthalmically compatible wearing of the contact lens by a lens wearerat least for one day. In certain embodiments, the lens body has two ormore of the foregoing features, such as oxygen permeability, watercontent, surface wettability, modulus, and design. In additionalembodiments, the lens body has three or more of the foregoing features.As used herein, ophthalmically compatible can be understood to refer tothe wearing of the present lenses by a lens wearer with little or nodiscomfort, and little or no occurrence of features associated withexisting silicone hydrogel contact lenses, such as lipid or proteindeposition, corneal staining, and the like. In certain embodiments, thelens body has all of the aforementioned properties useful in lenses thatare worn for at least one day, including daily wear lenses. In furtherembodiments, the lens body has all of the aforementioned propertiesuseful in lenses that are worn for about thirty days, includingcontinuous wear contact lenses.

Certain embodiments, such as the present daily wear lenses, of thecontact lenses comprise a hydrophilic silicon-containing polymericmaterial that comprises units from a hydrophilic silicon-containingmacromer, such as one hydrophilic silicon-containing macromer. Otherembodiments, including the present continuous wear contact lenses, ofthe contact lenses comprise a hydrophilic silicon-containing polymericmaterial that comprises units from two different hydrophilicsilicon-containing macromers, each macromer having a different molecularweight.

Embodiments of the present silicone hydrogel contact lenses comprise alens body having an oxygen permeability of at least about 70 barrers, awater content of at least about 30% by weight, a modulus less than about1.4 mPa, and a contact angle on a surface of the lens body less thanabout 60 degrees. In some embodiments, the lens body has an oxygenpermeability greater than about 110 barrers. In some embodiments, thelens body has a water content greater than about 45% by weight. In someembodiments, the lens body has a modulus less than about 0.9 mPa. Forexample, one embodiment of the present silicone hydrogel contact lensescomprises a lens body that has an oxygen permeability of at least about115 barrers, a water content of about 48% by weight, and a modulus ofabout 0.84 mPa. As another example, one embodiment of the presentsilicone hydrogel contact lenses comprises a lens body that has anoxygen permeability from about 70 barrers to about 100 barrers, a watercontent of at least about 50% by weight, and a modulus from about 0.3mPa to about 0.5 mPa. These and other features of the present lenses areincluded in the following description and summary above.

In another broad aspect, the present invention is directed to contactlenses which comprise lens bodies that are configured to be placed ordisposed on a cornea of an animal or human eye. The lens bodies comprisea hydrophilic silicon-containing polymeric material or materials. Thelens bodies have Dk's or oxygen permeabilities of greater than about 70barrers or about 75 barrers or about 80 barrers or about 85 barrers orabout 90 barrers or about 95 barrers or about 100 barrers or about 105barrers or about 110 barrers or about 115 barrers or about 120 barrersor about 125 barrers or about 130 barrers or about 150 barrers or about180 barrers or about 200 barrers, and equilibrium water contents ofgreater than about 15% or about 30% or about 35% or about 40% by weight.The present contact lenses are ophthalmically compatible, as definedherein, and are advantageously adapted and structured and/or areeffective for continuous wear on a cornea of a human or animal eye, forexample, for about 1 day or for about 5 days or for at least about 5days or about 10 days or about 20 days or about 30 days or more.

As used herein, the term “ophthalmically compatible” as applied to thepresent contact lenses and lens bodies may also be understood to meanthat such lenses and lens bodies are effective to provide the followingfeatures in continuous wear applications: (1) allow oxygen to reach thecornea of an eye wearing the lens in an amount sufficient for long termcorneal health; (2) cause no substantial undue corneal swelling or edemain an eye wearing the lens, for example, cause no more than about 5% orabout 10% corneal swelling after being worn on a cornea of an eye duringan overnight sleep; (3) allow movement of the lens on the cornea of aneye wearing the lens sufficient to facilitate tear flow between the lensand the eye, in other words, does not cause the lens to adhere to theeye with sufficient force to prevent substantially normal lens movement;(4) allow wearing of the lens on the eye without undue or significantdiscomfort and/or irritation and/or pain, for example, allow wearing ofthe lens with substantial comfort and/or substantial freedom fromirritation and/or substantial freedom from pain; and (5) inhibit orsubstantially prevent lipid and/or protein deposition sufficient tosubstantially interfere with the functioning of the lens during wear,for example, inhibit or substantially prevent lipid and/or proteindeposition sufficient to cause the lens wearer to remove the lensbecause of such deposition. Advantageously, such ophthalmicallycompatible contact lenses and lens bodies in addition inhibit, reduce,or even substantially prevent, corneal staining after the lens iscontinuously worn on a cornea of an eye, for example, during anovernight sleep.

Corneal staining is a measure of corneal epithelium cell damage ordestruction. The corneal epithelium is about 50 microns thick andcomprise 5-7 layers of cells. The epithelium is constantly regeneratedwith the outermost layer of cells sloughing off into the tear film withthe assistance of blinking. The innermost cell layer is pushed forwardby new cell growth beneath and this layer gradually transforms to becomethe outermost layer of cells following repeated cycles of new growthover about 7 days. Damaged or dead epithelial cells are stained whenexposed to sodium fluorescein. Thus, the degree of such staining can beused to measure the degree of cell damage/destruction. Some degree ofcorneal staining is often present with the wearing of conventionaldaily-wear and continuous wear contact lenses, and can occur evenwithout contact lens wear.

The use of sodium fluorescein is routinely used in clinical practice toidentify the degree of corneal epithelial damage. This is because sodiumfluorescein can passively accumulate into damaged cells or pool in areaswhere cells have been removed. One can determine the clinicalsignificance of epithelial damage and, therefore, its management byevaluating both the extent of area of cornea which shows fluoresceinstaining as well as whether the fluorescein is able to penetrate anddiffuse into the corneal stroma. The faster the time taken for thediffusion to occur into the stroma the greater number of layers havebeen damaged. Furthermore, the pattern of the staining is also a crucialindicator of the likely aetiology of the corneal staining e.g.superficial punctuate keratitis, superior epithelial arcuate lesions(SEALs), foreign body tracking, arcuate staining, etc. Grading scaleshave been developed for quantifying corneal staining and are well known.See Terry R L et al, “Standards for Successful Contact Lens Wear,”Optom. Vis. Sci. 70(3):234-243, 1993.

In one embodiment, the present lenses are structured and/or havecombinations of properties so as to substantially inhibit, evensubstantially prevent, corneal staining after the lens is continuouslyworn during an overnight sleep or for at least 1 day or at least 5 daysor at least 10 days or at least 20 days or at least 30 days. Forexample, the wearing of the present lenses advantageously may result incorneal staining (staining grading scale of 1.0 or more) incidences ofless than about 30% or about 20% or about 10%, based on a representativepopulation of lens wearers.

In the immediately preceding paragraph, the type of corneal stainingconsidered is inferior corneal dehydration staining. This stainingcharacteristically occurs in the inferior half of the cornea where thedehydration of the tear film on the anterior surface of the lens isgreatest and during wear creates an osmotic gradient that draws waterfrom the contact lens. If the lens is thin enough or the material has apropensity to lose water, e.g., has a relatively high ionoflux, then theosmotic gradient can be sufficiently great to dehydrate the tear filmunderneath the contact lens and subsequently dehydrate the cornealepithelium. This dehydration of the epithelium results in corneal damageand therefore corneal staining by fluorescein. This staining is usuallylimited to the superficial 2-3 layers of the epithelium and spread overthe inferior portion of the cornea, but if the stimulus is sufficientlygreat, damage can be deep and severe allowing rapid diffusion offluorescein into the stroma. The staining can occur rapidly within a fewhours of lens insertion but usually takes 4-6 hours or more. Likewisethe epithelial damage can resolve rapidly within 2-3 hours once thestimulus for dehydration has been removed. The greater the stimulus thefaster the staining will be induced and the longer it will take to healbut typically it would not take more than 4-6 hours to resolve.

In one embodiment, the lens bodies of the present contact lenses mayhave combinations of properties, including effective or appropriateionofluxes, to substantially inhibit, or even substantially prevent,corneal staining, as described herein. In one useful embodiment, thepresent lens bodies have ionofluxes of no greater than about 5, morepreferably no greater than about 4 or about 3, for example, no greaterthan about 2 or about 1 or less. Ionoflux is expressed as 10⁻³ mm²/min.

The ophthalmically compatible lens bodies, of the present contact lensesmay have no surface treatment or modification, for example, may beproduced without surface treatment or modification, such as on theanterior face and/or posterior face of the lens body, to enhance surfacewettability and/or one or more other beneficial properties of the lensbodies. Advantageously, no such surface treatment or modification isprovided on either the anterior face or the posterior face of thepresent ophthalmically compatible lens bodies. By not having suchsurface treatment or modification, the lens manufacturing process isless complex and expensive, and more efficient. Further, with no suchsurface treatment/modification, the present lens bodies advantageouslyhave more reproducible and/or more homogeneous surfaces. In addition,the lens wearer is not exposed to a surface treatment on the lens, whichmay, in and of itself, cause eye irritation and the like.

The oxygen permeability of the present lens bodies is measured with thecontact lens in the wet or fully hydrated state. The oxygen permeabilityor Dk is expressed as 10⁻¹⁰ (ml O₂ mm)/(cm² sec mm Hg) or barren.Preferably, the lens body has a Dk of at least about 70 barrers or about75 barrers or about 80 barrers or about 85 barrers or about 90 barrersor about 95 barrers or about 100 barrers or about 105 barrers or about110 barrers or about 115 barrers or about 120 barrers or about 125,barrers or about 130 barrers, or about 150 barrers or about 180 barrersor even at least about 200 barrers or more. The relatively high valuesof Dk of the present ophthalmically compatible lens bodies are highlyadvantageous in that oxygen is substantially accessible to the cornea ofan eye even when a contact lens is located on the cornea continuouslyfor a prolonged period of time, as described herein.

An additional mechanical property that may be effective in providing thepresent ophthalmically compatible contact lenses and lens bodies iselongation. The present lens bodies have sufficient elongations tofacilitate lens handling ease, lens structural integrity, lens wearcomfort, effective lens movement on the cornea and the like benefits.Lens bodies with insufficient elongation often suffer deficiencies inone or more of these areas. In a very useful embodiment, the presentlens bodies have elongations of at least about 90% or about 100% orabout 120%. Lens bodies having elongations of at least about 180% orabout 200% are very useful.

The Dk values of the present lens bodies, together with the equilibriumwater contents and/or the relatively low ionofluxes and/or therelatively high elongations of the present lens bodies effectivelyfacilitate ophthalmic compatibility of the present contact lenses and/orenhanced safety and comfort of the wearer of the present contact lenses,making continuous wear of such lenses more beneficial for the lenswearer.

Moreover, in addition to the present ophthalmically compatible lensbodies having useful or effective Dk values and equilibrium watercontents, and advantageously relatively low ionofluxes, such lens bodiespreferably have sufficient structural or mechanical characteristics,such as modulus to reduce lens/eye interactions such as SEALs, contactlens papillary conjunctivitis (CLPC) and the like, tear strength, and/orone or more of the like mechanical properties, to allow or at leastfacilitate the lens bodies being able to withstand continuous contactlens wear for extended or prolonged periods of time, as describedherein.

The present ophthalmically compatible lens bodies have sufficientmodulus for use as continuous wear contact lenses. In one usefulembodiment, the modulus of the lens body is about 1.5 mPa, about 1.4mPA, or about 1.2 mPa or less, preferably about 1.0 mPa or less and morepreferably about 0.8 mPa or less or about 0.5 mPa or less or about 0.4mPa or less or about 0.3 mPa or less. For example, one embodiment of thepresent lenses has a modulus of about 0.84 mPa. Another embodiment ofthe present lenses has a modulus from about 0.3 mPa to about 0.5 mPa.Lens bodies which have sufficient modulus for use as continuous wearcontact lenses, but reduced modulus relative to prior art continuouswear lenses, for example, less than 1.0 MPa, are advantageous, forexample, for the comfort of the wearer of the continuous wear contactlens.

In a particularly useful aspect of the present invention, the presentcontact lenses include a lens body comprising a hydrophilicsilicon-containing polymeric material. In one embodiment, the polymericmaterial comprises units from at least two silicon-containing macromershaving different molecular weights, and preferably different chemicalstructures. Advantageously, one of the macromers has a number averagemolecular weight greater than about 5,000 or greater than about 8,000 orgreater than about 10,000. In another embodiment, the polymeric materialcomprises units from only one silicon-containing macromer. For example,an embodiment of the present lenses comprises units of asilicon-containing macromer having a number average molecular weight ofat least about 10,000.

The polymeric material may comprise units from a silicon-containingmacromer having a number average molecular weight of less than about5,000, for example, less than about 3,000 or less than about 2,000.

When units from two silicon-containing macromers are included in thepolymeric material, such macromers advantageously have number averagemolecular weights which differ by at least about 3000 or about 5000,more preferably by at least about 10,000. In one useful embodiment,units from a high molecular weight silicon-containing macromer arepresent in the polymeric material in a greater amount by weight than areunits of a low molecular weight silicon-containing macromer. Forexample, the weight ratio of high molecular weight macromer to lowmolecular weight macromer used to produce the present lens bodies mayrange from about 1.5 or about 2 to about 5 or about 7.

Without wishing to limit the invention to any particular theory ofoperation, it is believed that the use of two different molecular weightsilicon-containing macromers in producing the present lens bodies isadvantageous in providing appropriate or effective high oxygenpermeability and appropriate or effective equilibrium water contentand/or relatively low ionoflux while providing lens bodies effective foruse in continuous wear contact lenses, for example, ophthalmicallycompatible contact lenses that can be worn for about thirty days, ifdesired. The use of different molecular weight silicon-containingmacromers provides compatibility with the other components used toproduce the lens bodies, and may provide a degree of heterogeneity inthe present lens bodies, for example, on a molecular level, that atleast facilitates providing a lens body having a desirable combinationof physical properties which facilitates the lens body being highlyadvantageous for use in a continuous wear contact lens. In otherembodiments comprising units from one silicon-containing macromer,appropriate lens properties can be obtained that facilitate use of thelenses on a daily basis, such as for overnight wear.

In one useful embodiment, one of the silicon-containing macromers,preferably the low molecular weight macromer, is mono-functional, thatis it comprises only one group per molecule which participates in thepolymerization reaction to form the silicon-containing polymericmaterial. Without wishing to limit the invention to any particulartheory of operation, it is believed that the mono-functional macromerfacilitates or enhances component compatibility and/or heterogeneity,for example, on a molecular level, of the polymeric material. That is,the morphology of the polymeric material of the lens body is believed tobe sufficiently non-uniform or heterogenous such that different phasedomains are present in the polymeric material. This enhancedheterogeneous morphology is believed to enhance the ophthalmiccompatibility of the polymeric material and/or to increase at least oneof the Dk and the equilibrium water content and/or reduce the ionoflux,while maintaining or even reducing the modulus of the polymericmaterial, relative to a similar polymeric material comprising units fromonly one silicon-containing macromer or relative to a similar polymericmaterial comprising units from two silicon-containing macromers both ofwhich have at least two functional groups per molecule.

In any event it has been found that contact lenses with unique andadvantageous combinations of properties, which combinations ofproperties make the present lenses ophthalmically compatible, andadvantageously highly effective for continuous or extended wear, cansurprisingly be provided by selecting and processing macromers andmonomers, as described herein, into lens bodies of contact lenses.

There is no limitation in a composition of the contact lenses of thepresent invention so long as the lenses have the combinations ofproperties and/or perform in daily wear applications or continuous orextended wear applications as set forth herein.

In one embodiment, contact lenses in accordance with the presentinvention include a polymer containing units from a hydrophilicsiloxanyl methacrylate shown by formula I.

wherein, X₁ is a polymerizable substituent shown by the followingformula:

wherein, R1, R2, R3 and R4 are groups independently selected fromhydrocarbon groups having 1 to about 12 carbon atoms and a siloxanylgroup, such as a trimethylsiloxy group; and the structure [Y1] is apolysiloxane backbone comprising not less than 2 siloxane units; R5 is ahydrogen or a methyl group; Z1 is a group selected from —NHCOO—,—NHCONH—, —OCONH—R6-NHCOO—, —NHCONH—R7-NHCONH— and —OCONH—R8-NHCONH—,with R6, R7 and R8 independently selected from hydrocarbon groups having2 to about 13 carbon atoms; m is an integer from 0 to about 10; n is aninteger from about 3 to about 10; p is 0 when m is 0 and 1 when m is 1or greater; and q is an integer from 0 to about 20.

In formula I, the structural unit Y1 may have the following formula

wherein R9 and R10 are groups selected from hydrocarbon groups having 1to about 12 carbon atoms, for example, methyl groups, hydrocarbon groupssubstituted with one or more fluorine atoms, trimethylsiloxy groups, andhydrophilic substituents, and may be different from each other in thesequential chain; and r is an integer from about 7 to about 1000.

Use of such a hydrophilic siloxanyl methacrylate in accordance with thepresent invention provides contact lenses with high oxygen permeability,reduced deposition of proteins and lipids, superior or enhancedmaintenance of lens water wettability during continuous lens wear,acceptable lens movement on the cornea of an eye, and reduced adhesionto a cornea.

In one embodiment, at least one of R1, R2, R3 and R4 may be selectedfrom the groups shown by the following formulas (1a), (2a) and (3a)

wherein, g is an integer from 1 to about 10.

One or more hydrophilic substituents may be included in thesilicon-containing monomers and may be, for example, selected fromlinear or cyclic hydrocarbon groups linked with at least one substituentselected from hydroxyl groups and oxyalkylene groups, such as groupsshown by the following formulas (3b) and (4b):

—R21(OH)_(i)  (3b)

wherein, R21 is a hydrocarbon group having about 3 to about 12 carbonatoms and may have —O—, —CO— or —COO— group inserted between carbonatoms; provided that the number of hydroxyl groups on the same carbonatom is limited to only one, and i is an integer larger than 1;

—R22-(OR23)_(j)—OZ2  (4b)

wherein R22 is a hydrocarbon group having about 3 to about 12 carbonatoms and may have —O—, —CO— or —COO— group inserted between carbonatoms; R23 is a hydrocarbon group having about 2 to about 4 carbon atomsand the number of carbon atoms may be different from each other when jis not less than 2; j is an integer from 1 to about 200; Z2 is a groupselected from hydrogen, hydrocarbon groups having about 1 to about 12carbon atoms and —OOCR24, where R24 is a hydrocarbon group having about1 to about 12 carbon atoms.

Examples of hydrophilic groups comprise, without limitation: monohydricalcohol substituents such as —C₃H₆OH, —C₈H₁₆OH, —C₃H₆OC₂H₄OH,—C₃H₆OCH₂CH(OH)C₃, —C₂H₄COOC₂H₄OH, —C₂H₄COOCH₂CH(OH)C₂H₅ and the like;polyhydric alcohol substituents such as —C₃H₆OCH₂CH(OH)CH₂OH,—C₂H₄COOCH₂CH(OH)CH₂OH, —C₃H₆OCH₂C(CH₂OH)₃ and the like; andpolyoxyalkylene substituents such as —C₃H₆(OC₂H₄)₄OH, —C₃H₆ (OC₂H₄)₃₀OH,—C₃H₆(OC₂H₄)₁₀OCH₃, —C₃H₆(OC₂H₄)₁₀, —(OC₃H₆)₁₀OC₄H₉ and the like. Amongthese, particularly useful groups comprise: alcohol substituents such as—C₃H₆OH, —C₃H₆OCH₂CH(OH)CH₂OH and —C₃H₆OC₂H₄OH; and polyoxyethylenesubstituents such as —C₃H₆(OC₂H₄)_(k)OH and —C₃H₆(OC₂H₄)_(L)CH₃ whereineach of k and 1 independently is an integer from about 2 to about 40,preferably about 3 to about 20, from the viewpoints of superiorhydrophilicity and oxygen permeability.

One or more fluorine-containing substituents provide staining resistanceto the polymeric material, but an excess substitution may impairhydrophilicity. A hydrocarbon substituent having 1 to about 12 carbonatoms linked with fluorine atoms is very useful. Such usefulfluorine-containing groups comprise, without limitation:3,3,3-trifluoropropyl group, 1,1,2,2-tetrahydrofluorooctyl group,1,1,2,2-tetrahydroperfluorodecyl group and the like. Among these,3,3,3-trifluoropropyl group is very useful in view of the hydrophilicityand oxygen permeability obtained in the resulting lens body.

Besides the hydrophilic substituents and the fluorine-containingsubstituents, substituents linked to silicon atoms may comprise, withoutlimitation, hydrocarbon groups having one to about 12 carbon atoms,trimethylsiloxy groups and the like, and may be the same or differentfrom each other. A very useful group is an alkyl group having 1 to about3 carbon atoms, and methyl group is particularly useful.

In the general formula I, m advantageously is an integer from 0 to about4. If m is about 5 or greater, the monomer may become too hydrophobic tobe compatible with the other monomers, giving a cloudiness duringpolymerization and difficulty in homogeneous mixing of the monomers. Inthe formula (3a), if g is greater than about 10, the monomer may havereduced compatibility with the other monomers.

The above described hydrophilic siloxanyl methacrylate may besynthesized by reacting 2-isocyanatoethyl methacrylate withsiloxanylalkyl alcohol.

The present contact lenses may have equilibrium water contents in arange of about 25-60% by weight, comprise hydrophilic silicon-containingpolymeric material, and have oxygen permeabilities, expressed as Dk, ofnot less than about 80 or about 90 or about 100 or about 110 or about120. The lenses may provide one or more, for example, at least 2 or 3 ormore, and advantageously all, of the following: reduced adsorption ofproteins and lipids to the inner part of lens; easy lens care,acceptable lens movement on the eye, acceptable stability in lens shape,flexibility and wear comfort, thus enabling use in continuous wearapplications. In one very useful embodiment, the present contact lensesare sufficiently ophthalmically compatible to be effective forcontinuous wear for at least 5 days or at least 10 days or at least 20days or at least 30 days.

Water contents less than 5% or less than 15% by weight are oftenundesirable due to an easy adsorption of lipids to lens, potentiallyresulting in adhesion of the lens to the cornea of the eye wearing thelens. Water contents over 60% are often undesirable, giving the lens lowstrength, lens dehydration, poor scratch resistance in handling, easyfracture and high adsorption of proteins. Lenses with oxygenpermeabilities lower than a Dk of about 80 are undesirable in continuouswear lenses. Lenses with tensile modulus less than about 0.2×10⁷dyne/cm² (MPa) are often undesirable due to relative instability in lensshape and difficulty in lens handling. Lenses with tensile modulus overabout 1.5×10⁷ dyne/cm² (Mpa) or about 2×10⁷ dyne/cm² (Mpa) areundesirable, for example, because of a significant decrease in lensmovement on the cornea and an increased occurrence of adhesion to thecornea, lens flexure problems, comfort issues during lens wearing andthe like concerns.

Among other useful hydrophilic silicon-containing monomers for thecontact lenses of the present invention are those having the structuresshown by the following formulas Ia and Ib because lenses from polymericmaterials including units for such monomers, for example, together withunits of other silicon-containing monomers, provide a well-balancedcombination of properties, including, but not limited to, water content,oxygen permeability and modulus, together with less deposition ofproteins and lipids, and are advantageously ophthalmically compatible:

wherein h is an integer from about 8 to about 70 and R11 is anon-polymerizable or non-functional group, for example, a hydrocarbongroup having about 1 to about 6 carbon atoms. In one very usefulembodiment R11 is —C₄H₉. The compound identified in formula (Ib), in oneembodiment, may be considered a macromer, for example, having amolecular weight in a range of about 1,000 to about 3,000 or about5,000. The integer h is selected to provide a macromer with the desiredmolecular weight. Such a macromer is particularly useful in combinationwith another silicon-containing macromer having a higher molecularweight, as described elsewhere herein.

For example, and without limitation, a compound of the general formulaI, for example, by proper selection of the value for “r”, can be amacromer having a number average molecular weight of at least about 5000or about 8,000 or about 10,000 to about 25,000 or more. Such a highmolecular weight macromer can be used in combination with a lowmolecular weight macromer, for example, as illustrated by formula Ib, toproduce lens bodies for contact lenses which are sufficientlyophthalmically compatible to be effective in continuous wearapplications, as described elsewhere herein. In one embodiment, the useof the combination of such high and low molecular weightsilicon-containing macromers to produce a contact lens body provides forenhanced ophthalmic compatibility and/or enhanced effectiveness in suchcontinuous wear applications relative to a substantially identicalcontact lens body produced without one of the high molecular weightmacromer or the low molecular weight macromer.

Any polymer which contains units from one or more hydrophilicsilicon-containing monomers and/or macromers described herein can beused in the contact lenses of the present invention. For example, thepolymer may include copolymers with the following copolymerizablecompounds: acrylic monomers such as methyl acrylate, ethyl acrylate andacrylic acid; methacrylic monomers such as methyl methacrylate, ethylmethacrylate, 2-hydroxyethyl methacrylate and methacrylic acid; siloxanemonomers such as tris(trimethylsiloxy)silylpropyl methacrylate,bis(trimethylsiloxy)methylsilylpropyl methacrylate,pentamethyldisiloxanepropyl methacrylate,tris(trimethylsiloxy)silylpropyloxyethyl methacrylate, andtris(polydimethylsiloxy)silylpropyl methacrylate; fluorosiloxanemonomers such as tri(dimethyltrifluoropropylsiloxy)silylpropylmethacrylate; fluoroalkyl monomers such as 2,2,2-trifluoroethylmethacrylate, 2,2,3,3,3-pentafluoropropyl methacrylate andhexafluoroisopropyl methacrylate; fluoroalkyl and fluoroalkylethermonomers containing hydroxyl group such as1,1,2,2-tetrafluoroethoxy-2-hydroxypropyl methacrylate; hydrophilicmonomers such a N-vinylpyrrolidone, N,N′-dimethylacrylamide andN-vinyl-N-methylacetamide; crosslinkable monomers such as ethyleneglycol dimethacrylate, tetraethylene glycol dimethacrylate andtetramethyldisiloxanebis (propylmethacrylate).

Among these, copolymers with siloxane methacrylates, fluoroalkylsiloxanemethacrylates, fluoroalkyl methacrylates, fluoroalkylether methacrylatescontaining hydroxyl groups, hydrophilic monomers, crosslinkable monomerswith two or more unsaturated groups within a molecule and siloxanemacromers with polymerizable unsaturated groups at molecular ends arepreferable because of well-balanced physical properties such as oxygenpermeability, stain deposition resistance and mechanical strength.Preferable hydrophilic monomers in the present invention are amidemonomers containing N-vinyl group, and N-vinylpyrrolidone orN-vinyl-N-methylacetamide, in particular, can provide a contact lenswith superior surface wettability.

An example, without limitation, of such a contact lens comprises apolymer material derived from about 30% to about 70% or about 80% byweight of hydrophilic silicon-containing monomer(s) or macromer(s),about 5% to about 50% by weight of N-vinylpyrrolidone, 0% to about 25%by weight of N-vinyl N-methylacetamide, 0% to about 15% by weight of2-hydroxybutyl methacrylate, 0 to about 10% by weight isobornylmethacrylate, 0% to about 15% methyl methacrylate, by weight and about0.005% to about 5% by weight of a crosslinker compound.

The contact lenses of the present invention can be manufactured byconventional lens manufacturing methods. Such methods comprise, forexample and without limitation a method by lathe-cutting of polymerblock followed by polishing, a method to cast a monomer (and a macromer)composition into a mold with corresponding lens shape followed bypolymerization, and a method to form only one face of lens by castingmethod using a polymerization mold then finish the other face bylathe-cutting and polishing method, etc.

Polymeric materials comprising units of a hydrophilic polysiloxanemonomer shown by the general formula II can be used for the contactlenses of the present invention:

wherein, R12 is hydrogen or methyl group; each of R13, R14, R15 and R16is independently selected from hydrocarbon groups having 1 to about 12carbon atoms and trimethylsiloxy groups; Y is selected from combinationsof the structural units (I′) and (II′) shown below, with the ratio ofthe structural unit (I′) and the structural unit (II′) being about 1:10to about 10:1 and total number of the structural units (I′) and (II′)being from about 7 to about 200 or about 1000; each of a and cindependently is an integer from 1 to about 20, d is an integer from 2to about 30; b is an integer from 0 to about 20; X is —NHCOO— group or—OOCNH—R16-NHCOO— group, wherein R16 is a hydrocarbon group having about4 to about 13 carbon atoms:

wherein, each of R17 and R18 is independently a hydrocarbon group having1 to about 12 carbon atoms or fluorinated hydrocarbon group having 1 toabout 12 carbon atoms, provided that at least one of R17 and R18 is afluorinated hydrocarbon group; and each R19 and R20 is independently ahydrocarbon group or an oxygen-containing group, provided that at leastone of R19 and R20 is an oxygen-containing group. Very useful oxygencontaining groups for use as R19 and/or R20 comprise, without limitation

—C₃H₆(OC₂H₄)_(e)OH

and

—C₃H₆(OC₂H₄)_(f)OCH₃

wherein e and f is an integer from about 2 to about 40, preferably about2 to about 20.

The monomer of formula II can be considered a macromer, for example, abifunctional macromer. For example, the molecular weight of the macromerof formula II can be controlled by controlling the number of structuralunits (I′) and (II′) in the macromer. In one useful embodiment, theformula II macromer has a relatively high molecular weight, for example,at least about 5000, and preferably in a range of about 10,000 to about25,000 or more (number average molecular weight). The formula IImacromer can be used alone, that is as the only silicon-containingmonomer, in the present contact lenses. Advantageously, the highmolecular weight macromer is used in combination with a low molecularweight macromer, as described elsewhere herein to form the polymericmaterial included in the present lenses or lens bodies.

In this embodiment, the units from monomer(s) or macromer(s) may make upabout 30% or about 40% to about 70% or about 80% by weight of thepolymeric material.

In the event that both high and low molecular weight silicon-containingmacromers are used, the high molecular weight macromer comprises atleast about 20% or about 30% or about 40% by weight of the polymericmaterials. In one useful embodiment, units from the combination of thehigh molecular weight macromer and the low molecular weight macromer areat least about 30% or about 40% or about 50% by weight of the polymericmaterial.

The above described monomer or macromer of Formula II may becopolymerized with one or more other monomers and/or macromers, forexample, as described elsewhere herein.

A contact lens comprising the above described polysiloxane monomer ormonomers (macromer or macromers) as a main or primary component can bemanufactured by conventional lens manufacturing methods such as thecasting method in which a monomer composition is injected into apolymerization mold with a corresponding lens shape followed by apolymerization. A lens manufactured by using a mold made of a materialwith polar groups at the surface of the mold, such as molds made ofethylene-vinyl alcohol (EVOH) copolymer, polyamide, and polyethyleneterephthalate, are preferred. Such molds are believed to be effective infacilitating the formation of a thick stable hydrophilic layer at thesurface of the lens body, little or no change in surface characteristicsduring continuous or extended wear of the lens, together withsubstantially stable lens performance, such as superior waterwettability and reduced deposition of proteins and lipids during suchwear. Advantageously, lenses produced in such molds, including EVOHmolds, have desired surface wettabilities without requiring a surfacetreatment or surface modification that is associated with certainexisting silicone hydrogel contact lenses.

In this specification, the structural units of the formulas [I] and [II]of the silicon-containing monomers or macromers are expressed as a blocktype linkage, but the present invention also comprises a random linkagetype.

It is preferable from the viewpoint of polymerization that polymerizableunsaturated groups are linked to the ends of siloxane chain andstructure of the unsaturated group is acrylate or methacrylate group. Asa linking group to Si atoms, hydrocarbon groups containing urethane orurea linkages are preferable, and may be linked to Si atoms throughoxyethylene groups. Urethane or urea linkages are highly polar andenhance the hydrophilic property and strength of the polymer. Astructure having two such groups can be formed by a reaction betweendiisocyanate linkages and a hydroxyl- or amine-containing moleculehaving about 2 to about 13 carbon atoms and may be linear, cyclic oraromatic types.

There are various synthesis methods for the hydrophilicsilicon-containing monomers (macromers). A number of such methods employreagents and reactions and synthesis strategies and techniques which areconventional and well known in the art, for example, in the art ofsilicone polymer chemistry.

An example of a useful synthesis method comprises the following: Aring-opening polymerization of a mixture of cyclic siloxane withhydrosilane groups (Si—H), cyclic siloxane with hydrocarbon groups, anddisiloxane with hydroxyalkyl groups at both ends, along with cyclicsiloxane with fluorine-substituted hydrocarbon groups in certain cases,is performed using an acidic catalyst, such as sulfuric acid,trifluoromethanesulfonic acid and acidic clay to obtainhydrosilyl-group-containing polysiloxane compounds having hydroxylgroups at both ends. In this case, siloxane compounds with variousdegrees of polymerization and introduction ratios of fluorine-containingsubstituent and hydrosilyl groups can be obtained by changing feedratios of each cyclic siloxane and disiloxane compounds used.

Isocyanate substituted acrylates or isocyanate substituted methacrylatesare then reacted with hydroxyl groups at the ends of polysiloxane toobtain urethane-containing fluorinated siloxane compounds withpolymerizable unsaturated groups at both ends.

The presently useful monofunctional macromers may be produced usingconventional and well known chemical synthesis techniques. For example,a monofunctional hydroxyl polysiloxane, such as a commercially availablemonofunctional hydroxyl polysiloxane, can be reacted with anisocyanate-substituted acrylate or an isocyanate-substitutedmethacrylate in the presence of a catalyst, for example, tin-containingcatalyst, at conditions effective to obtain a mono-terminated acrylateor methacrylate polysiloxane macromer.

Useful isocyanate-substituted methacrylates comprise, withoutlimitation, such monomers as methacryloxyethylisocyanate,methacryloylisocyanate, and the like and mixtures thereof. Isocyanatecompounds with acrylate or methacrylate groups obtained by reactinghydroxyl-group-containing acrylates or methacrylates, such ashydroxyethyl methacrylate and hydroxybutyl acrylate, with variousdiisocyanate compounds can also be utilized.

Hydrophilic polysiloxane monomer and/or macromers can be obtained byadding an unsaturated-hydrocarbon-group-containing hydrophilic compoundto the hydrosilane using a transition metal catalyst, such aschloroplatinic acid and the like, utilizing the so calledhydrosilylation reaction. In the hydrosilylation reaction, it is knownthat a dehydrogenation reaction occurs as a side reaction if an activehydrogen compound, such as hydroxyl group and carboxylic acid and thelike, is present. Therefore, if these active hydrogen atoms are presentin a hydrophilic compound to be introduced, the side reaction should besuppressed by protecting the active hydrogen atom in advance or addingbuffer agents. For example, see U.S. Pat. No. 3,907,851, the disclosureof which is incorporated in its entirety by reference herein.

Another route of synthesis is as follows: After synthesis of ahydrosilyl-group-containing polysiloxane compound having hydroxyl groupsat both ends, a hydrophilic group or moiety is introduced byhydrosilylation in advance, then polymerizable groups are introduced toboth ends of the siloxane by reacting with isocyanate-substitutedmethacrylate or the like.

In this case, if active hydrogen, which is reactive to the isocyanate,is present in the hydrophilic compound, the side reaction withisocyanate must be prevented, for example, by introducing a protectivegroup. Alternatively, for example, a silicate ester derivative, such asdimethoxy silane, a diethoxysilane compound, and the like, instead of acyclic siloxane, can be used as a starting raw material. Mixtures of twoor more hydrophilic polysiloxane monomers thus obtained can also beused.

Any polymer which comprises units from one or more hydrophilicsilicon-containing monomers and/or macromers described herein can beused in the contact lenses of the present invention.

At least one hydrophilic monomer may be employed as a comonomercomponent in addition to the hydrophilic silicon-containing monomer ormacromer. Preferably an amide monomer, for example, an amide monomercontaining an N-vinyl group, is useful to obtain superior transparency,staining resistance and surface wettability. Without wishing to limitthe invention to any particular theory of operation, it is believed thata phase-separated structure, on a molecular level, may be formed in thecopolymerization with the hydrophilic polysiloxane monomer (macromer) ormonomers (macromers) disclosed in the present invention, for example,due to differences in copolymerizability, molecular weight, polarity andthe like between two or more of these monomers resulting in providingstable staining resistance, enhanced hydrophilicity and enhanced oxygenpermeability, and preferably an enhanced degree of ophthalmiccompatibility.

An amide monomer containing an N-vinyl group may be selected, withoutlimitation from N-vinyl formamide, N-vinyl acetamide, N-vinylisopropylamide, N-vinyl-N-methyl acetamide, N-vinyl pyrrolidone, N-vinylcaprolactam and the like and mixtures thereof. N-vinyl-N-methylacetamide and N-vinyl pyrrolidone are very useful.

Useful polymeric materials in accordance with the present inventioncomprise copolymers obtained by addition of monomers other than thehydrophilic polysiloxane monomer(s) and the amide monomer containingN-vinyl group. Any monomer can be used in the present invention so longas it is copolymerizable, and hydrophilic monomers, among them, areuseful. Useful hydrophilic monomers have good compatibility with thehydrophilic polysiloxane monomer(s) and/or macromer(s) and also canfurther improve surface wettability of the polymeric material and modifywater content. Useful hydrophilic monomers comprise, for example andwithout limitation, monomers containing one or more hydroxyl groups,which monomers can improve mechanical properties, e.g., strength,elongation, tear strength and the like, such as 2-hydroxyethylmethacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropylmethacrylate, 2-hydroxybutyl methacrylate, 1-hydroxymethylpropylmethacrylate, 4-hydroxybutyl methacrylate and glycerol methacrylate;monomers containing fluorine-substituted groups such as3-(1,1,2,2-tetrafluoroethoxy)-2-hydroxypropyl methacrylate; andacrylates corresponding to the methacrylates set forth herein.2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate,2-hydroxybutyl methacrylate and mixtures thereof are very useful.

Other useful hydrophilic monomers includes, for example, and withoutlimitation, monomers containing carboxyl groups such as methacrylicacid, acrylic acid and itaconic acid; monomers containing alkylsubstituted amino groups such as dimethylaminoethyl methacrylate anddiethylaminoethyl methacrylate; acrylamide or methacrylamide monomerssuch as N,N′-dimethylacrylamide, N,N′-diethylacrylamide,N-methylacrylamide, methylenebisacrylamide and diacetoneacrylamide;monomers containing oxyalkylene groups such as methoxypolyethyleneglycol monomethacrylate and polypropylene glycol monomethacrylate andthe like and mixtures thereof.

Siloxanyl acrylates are useful comonomers, for example, to adjust oxygenpermeability. For example, such monomers comprise, without limitation,tris(trimethylsiloxy)silylpropyl methacrylate,bis(trimethylsiloxy)methylsilylpropyl methacrylatepentabmethyldisiloxanyl methacrylate and the like and mixtures thereof.Polymerizable polydimethylsiloxanes substituted with methacrylate groupsand the like and mixtures thereof can also be used for the similarobjective.

Other monomers, which can be utilized, comprise, without limitation,fluorinated monomers, such as fluoroalkyl acrylates and fluoroalkylmethacrylates, for example, trifluoroethyl acrylate, tetrafluoroethylacrylate, tetrafluoropropyl acrylate, pentabfluorpropyl acrylate,hexafluorobutyl acrylate, hexafluoroisopropyl acrylate, methacrylatescorresponding to these acrylates and the like and mixtures thereof.

Furthermore, alkyl acrylate monomers and alkyl methylacrylate monomerscan also be used if necessary and/or desired. They comprise, for exampleand without limitation, methyl acrylate, ethyl acrylate, n-propylacrylate, n-butyl acrylate, stearyl acrylate methacrylates correspondingto these acrylates and the like and mixtures thereof. In addition,monomers with high glass transition temperature (Tg), such as cyclohexylmethacrylate, tert-butyl methacrylate and isobornyl methacrylate and thelike and mixtures thereof can also be used to enhance mechanicalproperties.

Moreover, crosslinkable monomers other than hydrophilic polysiloxanemonomers can be used to improve mechanical properties and stability andadjust water content. For example, they comprise, without limitation,ethylene glycol dimethacrylate, diethylene glycol dimethacrylate,tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate,trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate,bisphenol A dimethacrylate, vinyl methacrylate; acrylates correspondingto these methacrylates; monomers containing one or more alkyl groups,such as, without limitation, triallyl isocyanurate, triallyl cyamurate,triallyl trimelitate and allylmethacrylate; siloxane derivatives such as1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane and the like andmixtures thereof.

Crosslinkable monomers linked with urethane group are particularlyuseful in providing compatibility and hydrophilicity, together withimprovement of mechanical properties. Bifunctional crosslinkablemonomers shown by the formula (10b) are useful:

wherein, R24 and R26 are independently selected from hydrogen and methylgroup; Z3 is an urethane linking group; R25 is selected from hydrocarbongroup having 2 to about 10 carbon atoms and polyoxyethylene groupexpressed by —(C₂H₄O)_(u)C₂H₄— wherein u is an integer from 2 to about40; t is an integer from 0 to about 10; s is 0 when t is 0 and 1 when tis 1 or greater.

Without wishing to limit the invention to any particular theory ofoperation, it is believed that the above bifunctional compounds havegood compatibilities and copolymerizability and contribute to strengthimprovement by intermolecular interaction because the hydrophilicpolysiloxane monomers have similar backbones, for example urethanegroup-containing backbones. Examples of crosslinkable monomers withurethane linkages including, without limitation,2-methacryloylcarbamoyloxyethyl methacrylate,2-2(2-methacryloxycarbamoyloxy)ethyl acrylate,2-(2-methacryloxyethylcarbamoyloxy)propyl methacrylate,2-methacryloxyethylcarbamoyloxytetraethylene glycol methacrylate and thelike and mixtures thereof.

A particularly useful crosslinkable monomer shown by the formula (11b)is:

These crosslinkable monomers can be used alone or in combination.

In order to improve a balance of characteristics of a hydrophilicpolymeric material, such as optical characteristics, oxygenpermeability, mechanical strength, recovery from deformation, stainingresistance during contact lens wearing, dimensional stability in tearand durability, mixed monomers of these copolymerizable monomers can beused.

An example, without limitation, of such a contact lens comprises apolymer material derived from about 30% to about 70% or about 80% byweight of hydrophilic silicon-containing monomer(s) or macromer(s),about 5% to about 50% by weight of N-vinylpyrrolidone, 0% or about 0.1%to about 25% by weight of N-vinyl N-methylacetamide, 0% or about 0.1% toabout 15% by weight of 2-hydroxybutyl methacrylate, 0% or about 0.1% toabout 15% by weight of methyl methacrylate, and about 0.005% to about 5%by weight of a crosslinker compound. Various additives may further beadded before or after polymerization, if necessary. Examples ofadditives comprise, without limitation, dyes or pigments with variouscoloring characteristics, UV absorbers and the like and mixturesthereof. Furthermore, when a lens is manufactured using a mold, moldreleasing agents such as surfactants and the like and mixtures thereofcan be added to improve separation of lens from the mold.

One embodiment of the present silicone hydrogel contact lenses comprisesa material having the United States Adopted Name (USAN) comfilcon A.

The contact lenses of the present invention can be manufactured byconventional lens manufacturing methods. The methods include, forexample a method by lathe-cutting of polymer block followed bypolishing, a method to cast a monomer (and a macromer) composition intoa mold with corresponding lens shape followed by polymerization, and amethod to form only one face of lens by casting method using apolymerization mold then finish the other face by lathe-cutting andpolishing method, etc.

A polymeric material used for a contact lens of the present invention isformed to an ophthalmologic lens by a mold method in which a monomermixture comprising, for example, one or more hydrophilic polysiloxanemonomers and an amide monomer containing N-vinyl group, is filled into amold, followed by a radical polymerization by the known method, or by aspin casting method in which a monomer mixture is fed in a rotatablehemisphere mold, followed by a polymerization. In these cases,polymerization of a solution of monomer mixture added with solvents in amold may be utilized to adjust the degree of polymerization or lensswelling ratio. If a solvent is included, solvents which dissolve themonomers effectively are advantageously used. Examples include, withoutlimitation alcohols such as ethanol and isopropanol; ethers such asdimethylsulfoxide, dimethylformamide, dioxane and tetrahydrofran;ketones such as methylethyl ketone; esters such as ethyl acetate; andthe like and mixtures thereof.

Any mold material can be used for mold polymerization or castingpolymerization, so long as it is substantially insoluble to monomermixture and lens can be separated after polymerization. For example,polyolefin resins such as polypropylene and polyethylene can be used,and materials having polar groups at a surface are preferable. As usedherein, a polar group means an atomic group with strong affinity withwater and comprises hydroxyl groups, nitrile groups, carboxyl groups,polyoxyethylene groups, amide groups, urethane groups and the like. Veryuseful mold materials are insoluble to a polymerization monomercomposition and have contact angles to water at least at the part forforming one lens surface, not higher than about 90°, preferably about65° to about 80°, by the sessile drop method. A contact lens formedusing a mold material having surface contact angle smaller than 80°shows particularly superior water wettability and stable performance inlipid deposition and the like. A mold material having surface contactangle smaller than 65° is not advantageous because of difficulty inseparating from the mold after polymerization, resulting in minutesurface damage or fractures at an edge part of lens. A mold materialsoluble to monomer compositions is also difficult to use because ofdifficulty in separating the lens as well as rough lens surfaces and lowtransparency.

More preferably, a mold material is a resin selected from polyamides,polyethylene terephthalates and ethylene-vinyl alcohol copolymers (EVOH)and the like. Ethylene-vinyl alcohol copolymers are particularly useful,for example, from the viewpoints of an easiness in molding, providing adimensionally stable mold and giving stable water wettability to themolded lens. An example of an ethylene-vinyl alcohol copolymer resinproduct to be used is available as “Soarlite” from The Japan SyntheticChem. Ind. Co. Ltd. or “EVAL” from Kuraray Co., Ltd. Various grades ofEVOH with ethylene copolymerization ratio of about 25-50% by mole can beused in the present invention.

As for initiating polymerization, a photopolymerization method may beused to initiate polymerization by UV or visible light irradiation inthe presence of photopolymerization initiators in a monomer mixture, ora radical polymerization method to thermally polymerize using azocompounds or organic peroxides. Examples of photopolymerizationinitiators comprise, without limitation, benzoin ethyl ether, benzyldimethyl ketal, alpha, alpha′-diethoxy acetophenone,2,4,6-trimethylbenzoyl diphenyl phosphine axide, and the like andmixtures thereof. Examples of organic peroxide comprise, withoutlimitation, benzoin peroxide, t-butyl peroxide and the like and mixturesthereof. Examples of azo compounds comprise, without limitation,azobisisobutyronitorile, azobisdimethylvaleronitorile and the like andmixtures thereof. Among them, a photopolymerization method is veryuseful due to providing a stable polymerization in a short cycle time.

The surface of the molded lens may be modified, if desired, by applyingplasma treatment, ozone treatment, corona discharge, graftpolymerization or the like. However, in a preferred embodiment, thepresent contact lenses have highly advantageous combinations ofproperties without requiring any surface treatment or modification.

Evaluation methods for lens characteristics in the Examples and theComparative Examples are as follows:

Water Content

A soft contact lens was immersed in phosphate buffer saline (PBS)solution at 23° C. for more than 16 hours. After taking out and quickwiping off of surface water, the lens was weighed precisely. The lenswas then dried at 80° C. in a vacuum dryer to a constant weight. Watercontent was calculated from a weight change as follows:

water content=(weight difference/weight before drying)×100(%)

Oxygen Permeability (Dk Value)

Dk value was determined by the so-called Mocon Method, for example usinga test instrument commercially available under the model designation ofMocon Ox-Tran System. This method is described in Tuomela et al U.S.Pat. No. 5,817,924, the disclosure of which is hereby incorporated inits entirety herein by reference.

The Dk value is expressed as barrers or 10⁻¹⁰ (ml O₂ mm)/(cm² sec mmHg).

Tensile Modulus

Test pieces of about 3 mm width were cut out from a central part of lensand tensile modulus (unit; MPa or 10⁷ dyne/cm²) was determined from aninitial slope of a stress-strain curve obtained by tensile test at therate of 100 mm/min in physiological saline solution at 25° C., usingAutograph (Model AGS-50B manufactured by Shimadzu Corp.).

Ionoflux

The ionoflux of a contact lens or lens body is measured using atechnique substantially similar to the so-called “Ionoflux Technique”described in Nicolson et al U.S. Pat. No. 5,849,811, the disclosure ofwhich is hereby incorporated in its entirety herein by reference.

Elongation

The elongation of a contact lens or lens body is measured in the fullyhydrated state. This measurement is conducted in a substantiallyconventional/standard way and involves pulling the specimen employing anInstron Machine.

Other Mechanical Properties

Other mechanical properties such as tensile strength, tear strength, andthe like, were measured using well known and standardized testingtechniques.

EXAMPLES

The following non-limiting examples illustrate various aspects andfeatures of the present invention

Synthesis Example 1 Synthesis of Polysiloxanediol Having HydrosilaneGroups (A1)

A mixture of 150 gms of octamethylcyclotetrasiloxane, 22.6 gms of1,3,5-trimethyltrifluoropropyl-cyclotrisiloxane, 5.2 gms of1,3,5,7-tetramethyl-cyclotetrasiloxane, 9.8 gms of1,3-bis(3-(2-hydroxyethoxy)propyl)tetramethyldisiloxane, 200 gms ofchloroform and 1.5 gms of trifluoromethane sulfonic acid was stirred for24 hours at 25° C., then washed repeatedly with purified water until apH of the mixture became neutral. After water was separated, chloroformwas distilled off under the reduced pressure. The residual liquid wasdissolved in acetone (36 gms), reprecipitated with methanol (180 gms),followed by removal of volatile components under vacuum from a separatedliquid to give a transparent viscous liquid. The said liquid was thesiloxanediol having hydrosilane groups expressed by the followingformula (H3R) with a yield of 125 gms. Here, although the structuralformula of the linking group Y is shown as a block structure composed ofeach siloxane unit, actually it contains random structures, and thisformula shows only a ratio of each siloxane unit. This is truethroughout the Synthesis Examples.

wherein,

A mixture of 125 gms of the siloxanediol described above, 40 gms ofpolyethyleneglycol allylmethylether (average molecular weight is 400),250 gms of isopropyl alcohol, 0.12 gms of potassium acetate, and 25 mgof chloroplatinic acid was charged into a flask with a reflux condensorand heated with stirring for 3 hours under reflux. The reaction mixturewas filtered, then isopropanol was distilled off under reduced pressure,followed by washing several times with a mixture of methanol/water.Further removal of volatile components under a vacuum gave a transparentviscous liquid with a yield of 120 gms. The liquid was a siloxanediolwithout hydrosilane groups (M3R), expressed by the following formula:

wherein,

A mixture of 120 gms of the siloxanediol (M3R) described above, 9.5 gmsof methacryloyloxyethyl isocyanate, 120 gms of dry 2-butanone and 0.05gms of dibutyltin dilaurate was poured in a brown-colored flask andstirred for 5 hours at 35° C., then further stirred after an addition of6 gms of methanol. Subsequently, 2-butanone was distilled off underreduced pressure, and the resulting liquid was washed several times witha mixture of methanol/water followed by removal of volatile componentsunder vacuum to give a transparent viscous liquid with a yield of 120gms. The liquid was the polysiloxane-dimethacrylate (M3-U) expressed bythe following formula:

wherein,

This material, identified as M3-U, has a number average molecular weightof about 15,000.

Synthesis Example 1A

Synthesis Example 1 is repeated with appropriate adjustments to theamounts of the components and/or conditions utilized to provide amacromer structured similarly to M3-U except that Y has the followingstructure:

This material, identified as M3-UU, has a number average molecularweight of about 20,000.

Synthesis Example 2

A mixture of 50 gms ofalpha-butyl-omega-[3-(2′hydroxyethoxy)propyl)polydimethylsiloxane, 10gms of methacryloyloxyethyl isocyanate, 150 gms of dry n-hexane and 0.2gms of dibutyltin dilaurate was poured in a brown-colored flask andheated for 2 hours under reflux, then further stirred after an additionof 6 gms of methanol. Subsequently, n-hexane was distilled off underreduced pressure, and the resulting liquid was washed several times withmethanol (30 gms)/water (15 gms) followed by removal of volatilecomponents under vacuum to give a transparent viscous liquid with ayield of 54 gms. The liquid was the polysiloxane-methacrylate (FMM)expressed by the following formula.

wherein,

This material, identified as FMM, has a number average molecular weightof about 1500.

Example 3

A mixture of 64 parts by weight of M3-U the polysiloxane described inthe Synthesis Example 1A, 10 parts by weight of N-vinyl-2-pyrrolidone(hereinafter NVP), 10 parts by weight of N-vinyl-N-methylacetamide(hereinafter “VMA”), 6 parts by weight of isobornyl methacrylate(hereinafter “IBM”), 10 parts by weight of methyl methacrylate(hereinafter “MMA”), 0.1 parts by weight of triallyl isocyanurate(hereinafter “TRIC”), and 0.1 parts by weight of2,4,6-trimethylbenzoyl-diphenylphosphine oxide (hereinafter “TPO”),which was added last to the mixture, was mixed with stirring. Themixture was injected into a mold for forming a contact lens made of anethylene vinyl alcohol resin (hereinafter “EVOH resin”) (made by TheJapan Synthetic Chem. Ind. Co., Ltd., Soarlite S), then irradiated byultraviolet (UV) light for 1 hour in a light exposure equipment to givea lens-shaped polymer. The lens thus obtained was soaked in ethylalcohol for 1.5 hours, then soaked in fresh ethyl alcohol for anadditional 1.5 hours, than soaked in an ethyl alcohol/water (1/1)mixture for 0.5 hours, soaked in deionized water for 3 hours, and thenplaced in PBS solution, and followed by autoclaving for 20 mins. Thelens thus obtained was transparent and flexible, and showed good waterwettability. Evaluation of physical properties showed results set forthin Table 1.

Examples 4, 5 and 6

Example 3 was repeated three times except that the mixtures formed hadthe compositions shown in Table 1. Each of the lenses thus obtained wastransparent and flexible, and showed good water wettability. Evaluationof physical properties showed results set forth in Table 1.

Examples 7, 8, 9 and 10

Example 3 was repeated four additional times except that the mixtureformed had the components and compositions shown in Table 1. In each ofthese examples, 10 parts by weight of FMM was included. Thus, each ofthe mixtures comprise one silicon-containing macromer having a molecularweight of about 15,000, and another silicon-containing macromer having amolecular weight of about 1,400. Each of the lenses thus obtained wastransparent and flexible, and showed good water wettability. Evaluationof physical properties showed results set forth in Table 1.

Example 11

A lens was prepared in accordance with Example 5.

The hydrated lens was placed into a 2% by weight aqueous solution ofglycerol monomethacrylate (GMMA)/glycerol dimethacrylate (GDMA) (97/3 byweight). The solution, with the lens included, was degassed and purgedwith nitrogen for 15 minutes. The aqueous solution was gently agitatedto maintain hydration. The solution was heated to 70° C. for 40 minutes.An aqueous solution of 2,2′-azobis(2-amidinopropane dihydrochloride(Vazo 56) was added to the lens/solution. Polymerization was allowed tooccur for 30 minutes. The lens was removed and repeatedly rinsed/soakedwith deionized water. The lens thus obtained was transparent andflexible, and showed good water wettability. Evaluation of physicalproperties showed results set forth in Table 1.

Comparative Examples 12 and 13

Two commercially available extended wear contact lenses were chosen forproperty testing. Evaluation of physical properties of these two lensesshowed results set forth in Table 1.

TABLE I Component Identification Composition (Mass % or Relative Parts)Examples Component Abbrev Description 3 4 5 6 7 8 9 10 11 Silicone M3-UPolysiloxanyl dimeth. 64 64 66 60 42 42 44 44 66 Macromer MW = about15,000 Imparts high Dk Silicone FM0411 Polysiloxanyl dimeth. 10 10 10 10Macromer M MW = about 1500 Imparts high Dk N-Vinyl 2- NVP Hydrophilic 1010 10 10 30 30 30 40 10 pyrrolidinone monomer N-Vinyl-N- VMA Hydrophilic10 12 18 20 10 10 10 0 18 methylacetamide monomer 2-Hydroxybutyl HOBHydrophilic 6 10 10 10 10 methacrylate monomer Glycerol GMMA Hydrophilicsee monomethacrylate monomer text (IPN Process) Glycerol GDMAHydrophilic see dimethacrylate monomer text Crosslinking agent (IPN)Isobornyl IBM Hydrophobic 6 6 6 6 6 6 6 6 methacrylate monomer MethylMMA Hydrophobic 10 8 methacrylate monomer Triallyl TAIC Crosslinking 0.10.1 0.1 0.1 0.1 0.1 isocyanurate agent Tetraethylene 4ED Crosslinking 42 1 glycol dimethacrylate agent Bis(2-ethylhexyl) Aerosol Nonreactive 00 0.5 0.5 0.5 0.5 0.5 0.5 0.5 sulfosuccinate OT surfactant sodium salt(AOT) (aids demolding) Diphenyl(2,4,6- Lucirin UV 0.1 0.1 0.1 0.1 0.10.1 0.1 0.1 0.1 trimethylbenzoyl) TPO Photoinitiator phosphine oxide2,2′-azobis(2- Vazo 56 Thermal initiator 0.1 amidino propane) Watersoluble dihydrochloride 12 13 B&L Ciba Pure Night Properties UnitsVision and Day EWC (Equil. % 34 37 44 36 36 38 44 42 42 36 24 WaterContent) Dk * 199 250 200 278 277 196 188 220 100 140 Modulus MPa 1.00.8 0.9 1.2 1.2 1.0 0.6 0.5 0.9 1.0 1.2 Elongation % 350 290 220 130 190251 357 355 193 271 Tear Strength N 69 59 32 23 64 69 83 96 183 163 Tb(Stress @ break) MPa 2.3 1.7 1.6 1.3 1.9 2.2 2.3 2.0 2.0 2.1 Ionoflux10⁻³ mm²/min 0.2 0.3 2.8 1.1 1.1 2.2 3.5 3.0 5.0 0.5 Surface ModifiedYes or No No No No No No No No No No Yes Yes

The present contact lenses, that is the contact lenses of Examples 3through 11, have unique and advantageous combinations of physicalproperties which make each of such lenses highly effective in continuousor extended wear applications, particularly when considered incomparison to the comparative commercially available lenses of Examples12 and 13.

Each of the lenses produced in Examples 3 to 11, after appropriateprocessing to remove extractable material and to hydrate the lens inpreparation for wear in a human eye, is placed in a human eye and wornfor six (6) hours. After this period of time, the lens is removed andthe eye is tested for corneal staining. Each of these lenses resulted inless than about 20% corneal staining.

Each of the lenses in Examples 3 to 11 has a combination of properties,for example, including water content, oxygen permeability, modulusand/or one or more other mechanical-related properties, and ionoflux,which provides for enhanced performance, for example, in terms of lensfunction effectiveness, wearer comfort and safety, in continuous wearapplications. The combinations of physical properties of the lenses ofExamples 3 to 11 are unmatched, for example, by the competitive lensesof Examples 12 and 13.

The lenses of Examples 3 to 11 are ophthalmically compatible duringcontinuous wear for at least about 5 days or about 10 days or about 20days or about 30 days. For example, such lenses do not adhere to thecornea during such continuous wear.

In short, the present contact lenses of Examples 3 to 11 illustrate thesubstantial continuous wear advantages of embodiments of the presentinvention.

In view of the disclosure herein, it can be appreciated that the presentcontact lenses comprise one or more features that are different thanexisting silicone hydrogel contact lenses. In one embodiment of thepresent lenses, the lens body has a water content of about 50% (such as47% or about 48%) and a ionoflux between about 4 and about 5. Inadditional embodiments, such a lens body has a Dk greater than 100.

The disclosure of U.S. Pat. No. 6,867,245 is hereby incorporated in itsentirety herein by reference.

A number of publications, patents, and patent applications have beencited hereinabove. Each of the cited publications, patents, and patentapplications are hereby incorporated by reference in their entireties.

While this invention has been described with respect to various specificexamples and embodiments, it is to be understood that the invention isnot limited thereto and that it can be variously practiced within thescope of the following claims.

1-55. (canceled)
 56. A silicone hydrogel contact lens comprising anophthalmically compatible, hydrophilic, silicone-containing polymeric,cast molded contact lens body having an oxygen permeability of at leastabout 100 barrers, an equilibrium water content greater than 40% byweight, wherein the lens body has a modulus in a range of about 0.4 MPato about 0.8 MPa.
 57. The contact lens of claim 56, wherein the lensbody is a polymerized reaction product of a precursor compositionconsisting essentially of copolymerizable monomers.
 58. The contact lensof claim 56, wherein the lens body comprises a polymerized reactionproduct of a precursor composition including an amide monomer selectedfrom the group consisting of N-vinyl-N-methylacetamide, N-vinylpyrrolidone and mixtures thereof.
 59. The contact lens of claim 57,wherein the lens body comprises a polymerized reaction product of aprecursor composition including an amide monomer selected from the groupconsisting of N-vinyl-N-methylacetamide, N-vinyl pyrrolidone andmixtures thereof.
 60. The contact lens of claim 58, wherein theprecursor composition further includes a silicon-containing monomer, ahydrophilic monomer and a crosslinking agent.
 61. The contact lens ofclaim 60, wherein the silicon-containing monomer is a bifunctionalsilicon-containing macromer having a number average molecular weight ina range of 10,000 to 25,000.
 62. The contact lens of claim 59, whereinthe precursor composition further includes a silicon-containing monomer,a hydrophilic monomer and a crosslinking agent.
 63. The contact lens ofclaim 56, wherein the contact lens body has an oxygen permeability of atleast 105 barrers, and an equilibrium water content of at least 45%. 64.A silicone hydrogel contact lens comprising an ophthalmicallycompatible, hydrophilic, silicone-containing polymeric, cast moldedcontact lens body comprising a polymerized reaction product of aprecursor composition including a plurality of non-silicon-containinghydrophilic monomers, including an N-vinyl amide monomer, wherein thelens body has an oxygen permeability of at least about 70 barrers, anequilibrium water content of at least 40%, and a modulus in a range ofabout 0.5 MPa to about 1.0 MPa.
 65. The contact lens of claim 64,wherein the lens body is a polymerized reaction product of a precursorcomposition consisting essentially of copolymerizable monomers.
 66. Thecontact lens of claim 64, wherein the N-vinyl amide monomer is an amidemonomer selected from the group consisting of N-vinyl-N-methylacetamide,N-vinyl pyrrolidone and mixtures thereof.
 67. The contact lens of claim65, wherein the N-vinyl amide monomer is an amide monomer selected fromthe group consisting of N-vinyl-N-methylacetamide, N-vinyl pyrrolidoneand mixtures thereof.
 68. The contact lens of claim 66, wherein theprecursor composition further includes a silicon-containing monomer, ahydrophilic monomer and a crosslinking agent.
 69. The contact lens ofclaim 67, wherein the precursor composition further includes asilicon-containing monomer, a hydrophilic monomer and a crosslinkingagent.
 70. The contact lens of claim 68, wherein the silicon-containingmonomer is a bifunctional silicon-containing macromer having a numberaverage molecular weight in a range of 10,000 to 25,000.